Aerosol generating article with upstream element

ABSTRACT

An aerosol-generating article is provided for producing an inhalable aerosol upon heating, the aerosol-generating article including: an aerosol-forming substrate including a gel composition, the gel composition including at least one gelling agent, at least one of an alkaloid compound and a cannabinoid compound, and an aerosol former; an upstream element upstream of the aerosol-forming substrate; and a recess extending from an upstream end of the aerosol-generating article, through the upstream element, and through at least a portion of the aerosol-forming substrate, in which a longitudinal inner surface of the recess is provided with a wrapper.

The present disclosure relates to an aerosol generating article for producing an inhalable aerosol upon heating. In particular, the present disclosure relates to an aerosol generating article for producing an inhalable aerosol upon heating comprising an aerosol-forming substrate comprising a gel composition, and an upstream element.

Aerosol generating articles in which an aerosol-forming substrate, such as a tobacco-containing substrate, is heated rather than combusted, are known in the art. Typically, in such heated smoking articles an aerosol is generated by the transfer of heat from a heat source to a physically separate aerosol-forming substrate or material, which may be located in contact with, within, around, or downstream of the heat source. During use of the aerosol generating article, volatile compounds are released from the aerosol-forming substrate by heat transfer from the heat source and are entrained in air drawn through the aerosol generating article. As the released compounds cool, they condense or nucleate to form an aerosol.

A number of prior art documents disclose aerosol-generating devices for consuming aerosol generating articles. Such devices include, for example, electrically heated aerosol-generating devices in which an aerosol is generated by the transfer of heat from one or more electrical heater elements of the aerosol-generating device to the aerosol-forming substrate of a heated aerosol generating article.

Aerosol generating articles in which a tobacco-containing substrate is heated rather than combusted present a number of challenges that were not encountered with conventional smoking articles. First of all, tobacco-containing substrates are typically heated to significantly lower temperatures compared with the temperatures reached by the combustion front in a conventional cigarette. This may have an impact on nicotine release from the tobacco-containing substrate and nicotine delivery to the consumer. At the same time, if the heating temperature is increased in an attempt to boost nicotine delivery, then the aerosol generated typically needs to be cooled to a greater extent and more rapidly before it reaches the consumer. However, technical solutions that were commonly used for cooling the mainstream smoke in conventional smoking articles, such as the provision of a high filtration efficiency segment at the mouth end of a cigarette, may have undesirable effects in an aerosol generating article wherein a tobacco-containing substrate is heated rather than combusted, as they may reduce nicotine delivery.

Additionally, in some aerosol generating articles of the prior art, the aerosol-forming substrate is heated externally by means of an external heater. However, this may be inefficient since the centre of the aerosol-forming substrate may be heated to a lesser extent than the periphery. It would therefore be desirable to provide an aerosol generating article which may be heated more efficiently.

Furthermore, some aerosol generating articles of the prior art are configured to allow air to pass through an aerosol-forming substrate. This may lead to a variation in the resistance to draw (RTD) over the course of the use of the aerosol generating article. For example, an aerosol-forming substrate when it is first used may have a higher RTD than a partially depleted aerosol-forming substrate.

With the above drawbacks of the prior art in mind, there is also a recognition that any improved aerosol generating article would also need to provide an efficient means of airflow management. Such airflow management must enable air to enter the article, entrain an aerosol from the aerosol-forming substrate, and leave the aerosol generating article while providing a satisfactory RTD and low RTD variability from one article to another.

Also, a need is generally felt for aerosol generating articles that are easy to use and have improved practicality.

Therefore, it would be desirable to provide a new and improved aerosol generating article adapted to achieve at least one of the desirable results described above. Further, it would be desirable to provide one such aerosol generating article that can be manufactured efficiently and at high speed.

The present disclosure relates to an aerosol generating article for producing an inhalable aerosol upon heating. The aerosol generating article may comprise an aerosol-forming substrate comprising a gel composition, the gel composition comprising at least one gelling agent, at least one of an alkaloid compound and a cannabinoid compound, and an aerosol former.

The provision of an aerosol-forming substrate comprising a gel composition may be desirable since it provides a uniform substrate that can generate a highly consistent aerosol. Additionally, the gel aerosol-forming substrate may be capable of generating an aerosol at a lower temperature than an aerosol-forming substrate comprising tobacco. This may provide a more efficient aerosol-generating system, the combination of the aerosol-generating device and aerosol generating article. Furthermore, this may advantageously reduce the need to cool the aerosol before it reaches the consumer.

The aerosol generating article my comprise an upstream element. The upstream element may be upstream of the aerosol-forming substrate.

The provision of an upstream element may advantageously protect the aerosol-forming substrate and prevent a user coming into direct contact with the gel composition within the aerosol-forming substrate. The upstream element may space the aerosol-forming substrate a certain distance from the upstream end of the aerosol generating article. This may be advantageous where the aerosol generating article is configured to be used with a heater which is not able to heat the upstream end of the aerosol generating article. This is because the upstream element may advantageously allow the aerosol-forming substrate to be located at the optimum position for heating when the aerosol generating article is inserted into an aerosol generating device. Additionally, the upstream element may act to prevent or reduce air entering the aerosol generating article through the upstream end of the aerosol generating article. This may help prevent air passing through the aerosol-forming substrate which may advantageously prevent variations in RTD over the use of the aerosol generating article. In this way, the upstream element may also act as an RTD buffer to control the RTD of the article irrespective of the RTD of the other individual components of the article.

The aerosol generating article my comprise a recess extending from the upstream end of the aerosol generating article, through the upstream element and through at least a portion of the aerosol-forming substrate.

The provision of the recess may advantageously allow the article to be heated using an internal heater such as a pin or a blade heater. This may facilitate more efficient heating of the aerosol-forming substrate. The inclusion of a recess is particularly advantageous since aerosol-forming substrates comprising a gel typically have a higher density than aerosol-forming substrates comprising tobacco. As a result, it will be less practical for a pin or a blade heater to be directly inserted into an aerosol-forming substrates comprising a gel compared to an aerosol-forming substrate comprising tobacco. In addition, the provision of a recess may prevent a heater coming into contact with the gel aerosol-forming substrate which may help to keep the heater clean.

According to the invention there is provided an aerosol generating article for producing an inhalable aerosol upon heating, the aerosol generating article comprises an aerosol-forming substrate comprising a gel composition, the gel composition comprises at least one gelling agent, at least one of an alkaloid compound and a cannabinoid compound, and an aerosol former. The aerosol generating article further comprises an upstream element upstream of the aerosol-forming substrate and a recess extending from the upstream end of the aerosol generating article, through the upstream element and through at least a portion of the aerosol-forming substrate.

The provision of an aerosol generating article according to the present invention may overcome many of the shortcomings of aerosol generating articles of the prior art. Firstly, the provision of an aerosol-forming substrate comprising a gel composition may be advantageous since it provides a uniform substrate that can generate a highly consistent aerosol. Additionally, the gel aerosol-forming substrate may be capable of generating an aerosol at a temperature lower than an aerosol-forming substrate comprising tobacco. This may provide a more efficient aerosol-generating system, the combination of the aerosol-generating device and aerosol generating article. Furthermore, this may advantageously reduce the need to cool the aerosol before it reaches the consumer.

The provision of the recess may advantageously allow for the article to be heated using an internal heater such as a pin or a blade heater. This may facilitate more efficient heating of the aerosol-forming substrate. This may also help to prevent the exterior surface of an aerosol generating device for use with the aerosol-forming substrate from becoming too hot. As set out above, the provision of an aerosol-forming substrate comprising a gel composition may reduce the temperature needed to generate an aerosol compared to an aerosol-forming substrate comprising tobacco. This, combined with the recess extending from the upstream end may synergistically help to more efficiently heat the aerosol-forming substrate and to reduce the temperature of an aerosol generating device using the aerosol generating article.

The provision of an upstream element may advantageously protect the aerosol-forming substrate and prevent a user coming into direct contact with the gel composition within the aerosol-forming substrate.

Furthermore, the upstream element can be used to provide greater control over the overall resistance to draw (RTD) of the aerosol generating article. In particular, the upstream element can advantageously be used to compensate for potential reductions in RTD due to evaporation of the gel composition during use, or due to the inclusion of other elements in the aerosol generating article having a relatively low resistance to draw. For example, in embodiments of the present invention including an intermediate hollow section which contributes virtually no RTD to the overall article, the upstream element can be used to add RTD to the aerosol generating article such that an acceptable level can still be provided.

Advantageously, the upstream element can provide an increase in the overall RTD without impacting the properties of the aerosol, due to the location of the upstream element upstream of the aerosol-forming substrate. If the desired level of RTD can be provided in large part due to the upstream element, this enables downstream elements to be used that provide minimal filtration of the aerosol. The aerosol generating article can therefore optimize aerosol delivery from the gel composition to the consumer whilst still retaining an optimal level of RTD throughout the smoking experience.

Alternatively or in addition, the upstream element can advantageously be adapted to compensate for reduction in length of other elements of the aerosol generating article so that an overall consistent length of the aerosol generating article can be retained. This may advantageously allow the aerosol-forming substrate to be located at the optimum position for heating when the aerosol generating article is inserted into an aerosol generating device. This compensation in length can be provided without impacting the properties of the aerosol.

Furthermore, the upstream element may advantageously provide a more uniform appearance at the upstream end of the aerosol generating article.

As used herein with reference to the present invention, the term “aerosol generating article” is used herein to denote an article wherein an aerosol-forming substrate is heated to produce and deliver inhalable aerosol to a consumer. As used herein, the term “aerosol-forming substrate” denotes a substrate capable of releasing volatile compounds upon heating to generate an aerosol.

A conventional cigarette is lit when a user applies a flame to one end of the cigarette and draws air through the other end. The localized heat provided by the flame and the oxygen in the air drawn through the cigarette causes the end of the cigarette to ignite, and the resulting combustion generates an inhalable smoke. By contrast, in heated aerosol generating articles, an aerosol is generated by heating an aerosol-forming substrate, such as tobacco. Known heated aerosol generating articles include, for example, electrically heated aerosol generating articles and aerosol generating articles in which an aerosol is generated by the transfer of heat from a combustible fuel element or heat source to a physically separate aerosol forming material. For example, aerosol generating articles according to the invention find particular application in aerosol-generating systems comprising an electrically heated aerosol-generating device having an internal heater which is adapted to be inserted into the recess of the aerosol generating article.

As used herein with reference to the present invention, the term “aerosol-generating device” refers to a device comprising a heater element that interacts with the aerosol-forming substrate of the aerosol generating article to generate an aerosol.

As used herein with reference to the present invention, the term “longitudinal” refers to the direction corresponding to the main longitudinal axis of the aerosol generating article, which extends between the upstream and downstream ends of the aerosol generating article. During use, air is drawn through the aerosol generating article in the longitudinal direction.

As used herein with reference to the invention, the terms “upstream” and “front”, and “downstream” and “rear”, are used to describe the relative positions of components, or portions of components, of the aerosol generating article in relation to the direction in which airflows through the aerosol generating article during use thereof. Aerosol generating articles according to the invention comprise a proximal end through which, in use, an aerosol exits the article. The proximal end of the aerosol generating article may also be referred to as the mouth end or the downstream end. The mouth end is downstream of the distal end. The distal end of the aerosol generating article may also be referred to as the upstream end. Components, or portions of components, of the aerosol generating article may be described as being upstream or downstream of one another based on their relative positions between the proximal end of the aerosol generating article and the distal end of the aerosol generating article. The front of a component, or portion of a component, of the aerosol generating article is the portion at the end closest to the upstream end of the aerosol generating article. The rear of a component, or portion of a component, of the aerosol generating article is the portion at the end closest to the downstream end of the aerosol generating article.

As used herein with reference to the present invention, the term “transverse” refers to the direction that is perpendicular to the longitudinal axis. Any reference to the “cross-section” of the aerosol generating article or a component of the aerosol generating article refers to the transverse cross-section unless stated otherwise.

As used herein with reference to the present invention, the term “length” denotes the dimension of a component of the aerosol generating article in the longitudinal direction. For example, it may be used to denote the dimension of the aerosol-forming substrate or the upstream element in the longitudinal direction.

According to the present invention, the aerosol-forming substrate comprises a gel composition that includes an alkaloid compound, or a cannabinoid compound, or both an alkaloid compound and a cannabinoid compound. In particularly preferred embodiments, the aerosol-forming substrate comprises a gel composition that includes nicotine.

Due to the provision of the recess extending from the upstream end of the aerosol generating article, through at least a portion of the aerosol-forming substrate, the aerosol-forming substrate includes a longitudinal opening to accommodate the recess. The longitudinal opening may extend along the full length of the aerosol-forming substrate. The longitudinal opening may extend through only an upstream portion of the aerosol-forming substrate. The aerosol-forming substrate may comprise and annular plug of a porous medium loaded with the gel composition. The porous medium may comprise at least one of cellulose acetate tow, crimped viscose, and crimped cotton.

Preferably, the gel composition comprises an alkaloid compound, or a cannabinoid compound, or both an alkaloid compound and a cannabinoid compound; an aerosol former; and at least one gelling agent. Preferably, the at least one gelling agent forms a solid medium and the glycerol is dispersed in the solid medium, with the alkaloid or cannabinoid dispersed in the glycerol. Preferably, the gel composition is a stable gel phase.

Advantageously, a stable gel composition comprising nicotine provides predictable composition form upon storage or transit from manufacture to the consumer. The stable gel composition comprising nicotine substantially maintains its shape. The stable gel composition comprising nicotine substantially does not release a liquid phase upon storage or transit from manufacture to the consumer. The stable gel composition comprising nicotine may provide for a simple consumable design. This consumable may not have to be designed to contain a liquid, thus a wider range of materials and container constructions may be contemplated.

The gel composition described herein may be combined with an aerosol-generating device to provide a nicotine aerosol to the lungs at inhalation or air flow rates that are within conventional smoking regime inhalation or air flow rates. The aerosol-generating device may continuously heat the gel composition. A consumer may take a plurality of inhalations or “puffs” where each “puff” delivers an amount of nicotine aerosol. The gel composition may be capable of delivering a high nicotine/low total particulate matter (TPM) aerosol to a consumer when heated, preferably in a continuous manner.

The phrase “stable gel phase” or “stable gel” refers to gel that substantially maintains its shape and mass when exposed to a variety of environmental conditions. The stable gel may not substantially release (sweat) or absorb water when exposed to a standard temperature and pressure while varying relative humidity from about 10 percent to about 60 percent. For example, the stable gel may substantially maintain its shape and mass when exposed to a standard temperature and pressure while varying relative humidity from about 10 percent to about 60 percent.

The gel composition includes an alkaloid compound, or a cannabinoid compound, or both an alkaloid compound and a cannabinoid compound. The gel composition may include one or more alkaloids. The gel composition may include one or more cannabinoids. The gel composition may include a combination of one or more alkaloids and one or more cannabinoids.

The term “alkaloid compound” refers to any one of a class of naturally occurring organic compounds that contain one or more basic nitrogen atoms. Generally, an alkaloid contains at least one nitrogen atom in an amine-type structure. This or another nitrogen atom in the molecule of the alkaloid compound can be active as a base in acid-base reactions. Most alkaloid compounds have one or more of their nitrogen atoms as part of a cyclic system, such as for example a heterocylic ring. In nature, alkaloid compounds are found primarily in plants, and are especially common in certain families of flowering plants. However, some alkaloid compounds are found in animal species and fungi. In this disclosure, the term “alkaloid compound” refers to both naturally derived alkaloid compounds and synthetically manufactured alkaloid compounds.

The gel composition may preferably include an alkaloid compound selected from the group consisting of nicotine, anatabine, and combinations thereof.

Preferably the gel composition includes nicotine.

The term “nicotine” refers to nicotine and nicotine derivatives such as free-base nicotine, nicotine salts and the like.

The term “cannabinoid compound” refers to any one of a class of naturally occurring compounds that are found in parts of the cannabis plant — namely the species Cannabis sativa, Cannabis indica, and Cannabis ruderalis. Cannabinoid compounds are especially concentrated in the female flower heads. Cannabinoid compounds naturally occurring in the cannabis plant include cannabidiol (CBD) and tetrahydrocannabinol (THC). In this disclosure, the term “cannabinoid compounds” is used to describe both naturally derived cannabinoid compounds and synthetically manufactured cannabinoid compounds.

The gel may include a cannabinoid compound selected from the group consisting of cannabidiol (CBD), tetrahydrocannabinol (THC), tetrahydrocannabinolic acid (THCA), cannabidiolic acid (CBDA), cannabinol (CBN), cannabigerol (CBG), cannabichromene (CBC), cannabicyclol (CBL), cannabivarin (CBV), tetrahydrocannabivarin (THCV), cannabidivarin (CBDV), cannabichromevarin (CBCV), cannabigerovarin (CBGV), cannabigerol monomethyl ether (CBGM), cannabielsoin (CBE),cannabicitran (CBT), and combinations thereof.

The gel composition may preferably include a cannabinoid compound selected from the group consisting of cannabidiol (CBD), THC (tetrahydrocannabinol) and combinations thereof.

The gel may preferably include cannabidiol (CBD).

The gel composition may include nicotine and cannabidiol (CBD).

The gel composition may include nicotine, cannabidiol (CBD), and THC (tetrahydrocannabinol).

The gel composition preferably includes about 0.5 percent by weight to about 10 percent by weight of an alkaloid compound, or about 0.5 percent by weight to about 10 percent by weight. of a cannabinoid compound, or both an alkaloid compound and a cannabinoid compound in a total amount from about 0.5 percent by weight to about 10 percent by weight. The gel composition may include about 0.5 percent by weight to about 5 percent by weight of an alkaloid compound, or about 0.5 percent by weight to about 5 percent by weight of a cannabinoid compound, or both an alkaloid compound and a cannabinoid compound in a total amount from about 0.5 percent by weight to about 5 percent by weight. Preferably the gel composition includes about 1 percent by weight to about 3 percent by weight of an alkaloid compound, or about 1 percent by weight to about 3 percent by weight of a cannabinoid compound, or both an alkaloid compound and a cannabinoid compound in a total amount from about 1 percent by weight to about 3 percent by weight. The gel composition may preferably include about 1.5 percent by weight to about 2.5 percent by weight of an alkaloid compound, or about 1.5 percent by weight to about 2.5 percent by weight of a cannabinoid compound, or both an alkaloid compound and a cannabinoid compound in a total amount from about 1.5 percent by weight to about 2.5 percent by weight. The gel composition may preferably include about 2 percent by weight of an alkaloid compound, or about 2 percent by weight of a cannabinoid compound, or both an alkaloid compound and a cannabinoid compound in a total amount of about 2 percent by weight. The alkaloid compound component of the gel formulation may be the most volatile component of the gel formulation. In some aspects water may be the most volatile component of the gel formulation and the alkaloid compound component of the gel formulation may be the second most volatile component of the gel formulation. The cannabinoid compound component of the gel formulation may be the most volatile component of the gel formulation. In some aspects water may be the most volatile component of the gel formulation and the alkaloid compound component of the gel formulation may be the second most volatile component of the gel formulation.

Preferably nicotine is included in the gel compositions. The nicotine may be added to the composition in a free base form or a salt form. The gel composition includes about 0.5 percent by weight to about 10 percent by weight nicotine, or about 0.5 percent by weight to about 5 percent by weight nicotine. Preferably the gel composition includes about 1 percent by weight to about 3 percent by weight nicotine, or about 1.5 percent by weight to about 2.5 percent by weight nicotine, or about 2 percent by weight nicotine. The nicotine component of the gel formulation may be the most volatile component of the gel formulation. In some aspects water may be the most volatile component of the gel formulation and the nicotine component of the gel formulation may be the second most volatile component of the gel formulation.

The gel composition additionally includes an aerosol-former. Ideally the aerosol-former is substantially resistant to thermal degradation at the operating temperature of the associated aerosol-generating device. Suitable aerosol-formers include, but are not limited to: polyhydric alcohols, such as triethylene glycol, 1, 3-butanediol and glycerine; esters of polyhydric alcohols, such as glycerol mono-, di- or triacetate; and aliphatic esters of mono-, di- or polycarboxylic acids, such as dimethyl dodecanedioate and dimethyl tetradecanedioate. Polyhydric alcohols or mixtures thereof, may be one or more of triethylene glycol, 1, 3-butanediol and, glycerine (glycerol or propane-1,2,3-triol) or polyethylene glycol. The aerosol-former is preferably glycerol.

The gel composition may include a majority of an aerosol-former. The gel composition may include a mixture of water and the aerosol-former where the aerosol-former forms a majority (by weight) of the gel composition. The aerosol-former may form at least about 50 percent by weight of the gel composition. The aerosol-former may form at least about 60 percent by weight or at least about 65 percent by weight or at least about 70 percent by weight of the gel composition. The aerosol-former may form about 70 percent by weight to about 80 percent by weight of the gel composition. The aerosol-former may form about 70 percent by weight to about 75 percent by weight of the gel composition.

The gel composition may include a majority of glycerol. The gel composition may include a mixture of water and the glycerol where the glycerol forms a majority (by weight) of the gel composition. The glycerol may form at least about 50 percent by weight of the gel composition. The glycerol may form at least about 60 percent by weight or at least about 65 percent by weight or at least about 70 percent by weight of the gel composition. The glycerol may form about 70 percent by weight to about 80 percent by weight of the gel composition. The glycerol may form about 70 percent by weight to about 75 percent by weight of the gel composition.

The gel composition additionally includes at least one gelling agent. Preferably, the gel composition includes a total amount of gelling agents in a range from about 0.4 percent by weight to about 10 percent by weight. More preferably, the composition includes the gelling agents in a range from about 0.5 percent by weight to about 8 percent by weight. More preferably, the composition includes the gelling agents in a range from about 1 percent by weight to about 6 percent by weight. More preferably, the composition includes the gelling agents in a range from about 2 percent by weight to about 4 percent by weight. More preferably, the composition includes the gelling agents in a range from about 2 percent by weight to about 3 percent by weight.

The term “gelling agent” refers to a compound that homogeneously, when added to a 50 percent by weight water/50 percent by weight glycerol mixture, in an amount of about 0.3 percent by weight, forms a solid medium or support matrix leading to a gel. Gelling agents include, but are not limited to, hydrogen-bond crosslinking gelling agents, and ionic crosslinking gelling agents.

The gelling agent may include one or more biopolymers. The biopolymers may be formed of polysaccharides.

Biopolymers include, for example, gellan gums (native, low acyl gellan gum, high acyl gellan gums with low acyl gellan gum being preferred), xanthan gum, alginates (alginic acid), agar, guar gum, and the like. The composition may preferably include xanthan gum. The composition may include two biopolymers. The composition may include three biopolymers. The composition may include the two biopolymers in substantially equal weights. The composition may include the three biopolymers in substantially equal weights.

Preferably, the gel composition comprises at least about 0.2 percent by weight hydrogen-bond crosslinking gelling agent. Alternatively or in addition, the gel composition preferably comprises at least about 0.2 percent by weight ionic crosslinking gelling agent. Most preferably, the gel composition comprises at least about 0.2 percent by weight hydrogen-bond crosslinking gelling agent and at least about 0.2 percent by weight ionic crosslinking gelling agent. The gel composition may comprise about 0.5 percent by weight to about 3 percent by weight hydrogen-bond crosslinking gelling agent and about 0.5 percent by weight to about 3 percent by weight ionic crosslinking gelling agent, or about 1 percent by weight to about 2 percent by weight hydrogen-bond crosslinking gelling agent and about 1 percent by weight to about 2 percent by weight ionic crosslinking gelling agent. The hydrogen-bond crosslinking gelling agent and ionic crosslinking gelling agent may be present in the gel composition in substantially equal amounts by weight.

The term “hydrogen-bond crosslinking gelling agent” refers to a gelling agent that forms non-covalent crosslinking bonds or physical crosslinking bonds via hydrogen bonding. Hydrogen bonding is a type of electrostatic dipole-dipole attraction between molecules, not a covalent bond to a hydrogen atom. It results from the attractive force between a hydrogen atom covalently bonded to a very electronegative atom such as a N, O, or F atom and another very electronegative atom.

The hydrogen-bond crosslinking gelling agent may include one or more of a galactomannan, gelatin, agarose, or konjac gum, or agar. The hydrogen-bond crosslinking gelling agent may preferably include agar.

The gel composition preferably includes the hydrogen-bond crosslinking gelling agent in a range from about 0.3 percent by weight to about 5 percent by weight. Preferably the composition includes the hydrogen-bond crosslinking gelling agent in a range from about 0.5 percent by weight to about 3 percent by weight. Preferably the composition includes the hydrogen-bond crosslinking gelling agent in a range from about 1 percent by weight to about 2 percent by weight.

The gel composition may include a galactomannan in a range from about 0.2 percent by weight to about 5 percent by weight. Preferably the galactomannan may be in a range from about 0.5 percent by weight to about 3 percent by weight. Preferably the galactomannan may be in a range from about 0.5 percent by weight to about 2 percent by weight. Preferably the galactomannan may be in a range from about 1 percent by weight to about 2 percent by weight.

The gel composition may include a gelatin in a range from about 0.2 percent by weight to about 5 percent by weight. Preferably the gelatin may be in a range from about 0.5 percent by weight to about 3 percent by weight. Preferably the gelatin may be in a range from about 0.5 percent by weight to about 2 percent by weight. Preferably the gelatin may be in a range from about 1 percent by weight to about 2 percent by weight.

The gel composition may include agarose in a range from about 0.2 percent by weight to about 5 percent by weight. Preferably the agarose may be in a range from about 0.5 percent by weight to about 3 percent by weight. Preferably the agarose may be in a range from about 0.5 percent by weight to about 2 percent by weight. Preferably the agarose may be in a range from about 1 percent by weight to about 2 percent by weight.

The gel composition may include konjac gum in a range from about 0.2 percent by weight to about 5 percent by weight. Preferably the konjac gum may be in a range from about 0.5 percent by weight to about 3 percent by weight. Preferably the konjac gum may be in a range from about 0.5 percent by weight to about 2 percent by weight. Preferably the konjac gum may be in a range from about 1 percent by weight to about 2 percent by weight.

The gel composition may include agar in a range from about 0.2 percent by weight to about 5 percent by weight. Preferably the agar may be in a range from about 0.5 percent by weight to about 3 percent by weight. Preferably the agar may be in a range from about 0.5 percent by weight to about 2 percent by weight. Preferably the agar may be in a range from about 1 percent by weight to about 2 percent by weight.

The term “ionic crosslinking gelling agent” refers to a gelling agent that forms non-covalent crosslinking bonds or physical crosslinking bonds via ionic bonding. Ionic crosslinking involves the association of polymer chains by noncovalent interactions. A crosslinked network is formed when multivalent molecules of opposite charges electrostatically attract each other giving rise to a crosslinked polymeric network.

The ionic crosslinking gelling agent may include low acyl gellan, pectin, kappa carrageenan, iota carrageenan or alginate. The ionic crosslinking gelling agent may preferably include low acyl gellan.

The gel composition may include the ionic crosslinking gelling agent in a range from about 0.3 percent by weight to about 5 percent by weight. Preferably the composition includes the ionic crosslinking gelling agent in a range from about 0.5 percent by weight to about 3 percent by weight by weight. Preferably the composition includes the ionic crosslinking gelling agent in a range from about 1 percent by weight to about 2 percent by weight.

The gel composition may include low acyl gellan in a range from about 0.2 percent by weight to about 5 percent by weight. Preferably the low acyl gellan may be in a range from about 0.5 percent by weight to about 3 percent by weight. Preferably the low acyl gellan may be in a range from about 0.5 percent by weight to about 2 percent by weight. Preferably the low acyl gellan may be in a range from about 1 percent by weight to about 2 percent by weight.

The gel composition may include pectin in a range from about 0.2 percent by weight to about 5 percent by weight. Preferably the pectin may be in a range from about 0.5 percent by weight to about 3 percent by weight. Preferably the pectin may be in a range from about 0.5 percent by weight to about 2 percent by weight. Preferably the pectin may be in a range from about 1 percent by weight to about 2 percent by weight.

The gel composition may include kappa carrageenan in a range from about 0.2 percent by weight to about 5 percent by weight. Preferably the kappa carrageenan may be in a range from about 0.5 percent by weight to about 3 percent by weight. Preferably the kappa carrageenan may be in a range from about 0.5 percent by weight to about 2 percent by weight. Preferably the kappa carrageenan may be in a range from about 1 percent by weight to about 2 percent by weight.

The gel composition may include iota carrageenan in a range from about 0.2 percent by weight to about 5 percent by weight. Preferably the iota carrageenan may be in a range from about 0.5 percent by weight to about 3 percent by weight. Preferably the iota carrageenan may be in a range from about 0.5 percent by weight to about 2 percent by weight. Preferably the iota carrageenan may be in a range from about 1 percent by weight to about 2 percent by weight.

The gel composition may include alginate in a range from about 0.2 percent by weight to about 5 percent by weight. Preferably the alginate may be in a range from about 0.5 percent by weight to about 3 percent by weight. Preferably the alginate may be in a range from about 0.5 percent by weight to about 2 percent by weight. Preferably the alginate may be in a range from about 1 percent by weight to about 2 percent by weight.

The gel composition may include the hydrogen-bond crosslinking gelling agent and ionic crosslinking gelling agent in a ratio of about 3:1 to about 1:3. Preferably the gel composition may include the hydrogen-bond crosslinking gelling agent and ionic crosslinking gelling agent in a ratio of about 2:1 to about 1:2. Preferably the gel composition may include the hydrogen-bond crosslinking gelling agent and ionic crosslinking gelling agent in a ratio of about 1:1.

The gel composition may further include a viscosifying agent. The viscosifying agent combined with the hydrogen-bond crosslinking gelling agent and the ionic crosslinking gelling agent appears to surprisingly support the solid medium and maintain the gel composition even when the gel composition comprises a high level of glycerol.

The term “viscosifying agent” refers to a compound that, when added homogeneously into a 25° C., 50 percent by weight water/50 percent by weight glycerol mixture, in an amount of 0.3 percent by weight., increases the viscosity without leading to the formation of a gel, the mixture staying or remaining fluid. Preferably the viscosifying agent refers to a compound that when added homogeneously into a 25° C. 50 percent by weight water/50 percent by weight glycerol mixture, in an amount of 0.3 percent by weight, increases the viscosity to at least 50 cPs, preferably at least 200 cPs, preferably at least 500 cPs, preferably at least 1000 cPs at a shear rate of 0.1 s-1, without leading to the formation of a gel, the mixture staying or remaining fluid. Preferably the viscosifying agent refers to a compound that when added homogeneously into a 25° C. 50 percent by weight water/50 percent by weight glycerol mixture, in an amount of 0.3 percent by weight, increases the viscosity at least 2 times, or at least 5 times, or at least 10 times, or at least 100 times higher than before addition, at a shear rate of 0.1 s-1, without leading to the formation of a gel, the mixture staying or remaining fluid.

The viscosity values recited herein can be measured using a Brookfield RVT viscometer rotating a disc type RV#2 spindle at 25° C. at a speed of 6 revolutions per minute (rpm).

The gel composition preferably includes the viscosifying agent in a range from about 0.2 percent by weight to about 5 percent by weight. Preferably the composition includes the viscosifying agent in a range from about 0.5 percent by weight to about 3 percent by weight. Preferably the composition includes the viscosifying agent in a range from about 0.5 percent by weight to about 2 percent by weight. Preferably the composition includes the viscosifying agent in a range from about 1 percent by weight to about 2 percent by weight.

The viscosifying agent may include one or more of xanthan gum, carboxymethyl-cellulose, microcrystalline cellulose, methyl cellulose, gum Arabic, guar gum, lambda carrageenan, or starch. The viscosifying agent may preferably include xanthan gum.

The gel composition may include xanthan gum in a range from about 0.2 percent by weight to about 5 percent by weight. Preferably the xanthan gum may be in a range from about 0.5 percent by weight to about 3 percent by weight. Preferably the xanthan gum may be in a range from about 0.5 percent by weight to about 2 percent by weight. Preferably the xanthan gum may be in a range from about 1 percent by weight to about 2 percent by weight.

The gel composition may include carboxymethyl-cellulose in a range from about 0.2 percent by weight to about 5 percent by weight. Preferably the carboxymethyl-cellulose may be in a range from about 0.5 percent by weight to about 3 percent by weight. Preferably the carboxymethyl-cellulose may be in a range from about 0.5 percent by weight to about 2 percent by weight. Preferably the carboxymethyl-cellulose may be in a range from about 1 percent by weight to about 2 percent by weight.

The gel composition may include microcrystalline cellulose in a range from about 0.2 percent by weight to about 5 percent by weight. Preferably the microcrystalline cellulose may be in a range from about 0.5 percent by weight to about 3 percent by weight. Preferably the microcrystalline cellulose may be in a range from about 0.5 percent by weight to about 2 percent by weight. Preferably the microcrystalline cellulose may be in a range from about 1 percent by weight to about 2 percent by weight.

The gel composition may include methyl cellulose in a range from about 0.2 percent by weight to about 5 percent by weight. Preferably the methyl cellulose may be in a range from about 0.5 percent by weight to about 3 percent by weight. Preferably the methyl cellulose may be in a range from about 0.5 percent by weight to about 2 percent by weight. Preferably the methyl cellulose may be in a range from about 1 percent by weight to about 2 percent by weight.

The gel composition may include gum Arabic in a range from about 0.2 percent by weight to about 5 percent by weight. Preferably the gum Arabic may be in a range from about 0.5 percent by weight to about 3 percent by weight. Preferably the gum Arabic may be in a range from about 0.5 percent by weight to about 2 percent by weight. Preferably the gum Arabic may be in a range from about 1 percent by weight to about 2 percent by weight.

The gel composition may include guar gum in a range from about 0.2 percent by weight to about 5 percent by weight. Preferably the guar gum may be in a range from about 0.5 percent by weight to about 3 percent by weight. Preferably the guar gum may be in a range from about 0.5 percent by weight to about 2 percent by weight. Preferably the guar gum may be in a range from about 1 percent by weight to about 2 percent by weight.

The gel composition may include lambda carrageenan in a range from about 0.2 percent by weight to about 5 percent by weight. Preferably the lambda carrageenan may be in a range from about 0.5 percent by weight to about 3 percent by weight. Preferably the lambda carrageenan may be in a range from about 0.5 percent by weight to about 2 percent by weight. Preferably the lambda carrageenan may be in a range from about 1 percent by weight to about 2 percent by weight.

The gel composition may include starch in a range from about 0.2 percent by weight to about 5 percent by weight. Preferably the starch may be in a range from about 0.5 percent by weight to about 3 percent by weight. Preferably the starch may be in a range from about 0.5 percent by weight to about 2 percent by weight. Preferably the starch may be in a range from about 1 percent by weight to about 2 percent by weight.

The gel composition may further include a divalent cation. Preferably the divalent cation includes calcium ions, such as calcium lactate in solution. Divalent cations (such as calcium ions) may assist in the gel formation of compositions that include gelling agents such as the ionic crosslinking gelling agent, for example. The ion effect may assist in the gel formation. The divalent cation may be present in the gel composition in a range from about 0.1 to about 1 percent by weight, or about 0.5 percent by weight to about 1 percent by weight.

The gel composition may further include an acid. The acid may comprise a carboxylic acid. The carboxylic acid may include a ketone group. Preferably the carboxylic acid may include a ketone group having less than about 10 carbon atoms, or less than about 6 carbon atoms or less than about 4 carbon atoms, such as levulinic acid or lactic acid. Preferably this carboxylic acid has three carbon atoms (such as lactic acid). Lactic acid surprisingly improves the stability of the gel composition even over similar carboxylic acids. The carboxylic acid may assist in the gel formation. The carboxylic acid may reduce variation of the alkaloid compound concentration, or the cannabinoid compound concentration, or both the alkaloid compound concentration and the cannabinoid compound within the gel composition during storage. The carboxylic acid may reduce variation of the nicotine concentration within the gel composition during storage.

The gel composition may include a carboxylic acid in a range from about 0.1 percent by weight to about 5 percent by weight. Preferably the carboxylic acid may be in a range from about 0.5 percent by weight to about 3 percent by weight. Preferably the carboxylic acid may be in a range from about 0.5 percent by weight to about 2 percent by weight. Preferably the carboxylic acid may be in a range from about 1 percent by weight to about 2 percent by weight.

The gel composition may include lactic acid in a range from about 0.1 percent by weight to about 5 percent by weight. Preferably the lactic acid may be in a range from about 0.5 percent by weight to about 3 percent by weight. Preferably the lactic acid may be in a range from about 0.5 percent by weight to about 2 percent by weight. Preferably the lactic acid may be in a range from about 1 percent by weight to about 2 percent by weight.

The gel composition may include levulinic acid in a range from about 0.1 percent by weight to about 5 percent by weight. Preferably the levulinic acid may be in a range from about 0.5 percent by weight to about 3 percent by weight. Preferably the levulinic acid may be in a range from about 0.5 percent by weight to about 2 percent by weight. Preferably the levulinic acid may be in a range from about 1 percent by weight to about 2 percent by weight.

The gel composition preferably comprises some water. The gel composition is more stable when the composition comprises some water. Preferably the gel composition comprises at least about 1 percent by weight, or at least about 2 percent by weight., or at least about 5 percent by weight of water. Preferably the gel composition comprises at least about 10 percent by weight or at least about 15 percent by weight water.

Preferably the gel composition comprises between about 8 percent by weight to about 32 percent by weight water. Preferably the gel composition comprises from about 15 percent by weight to about 25 percent by weight water. Preferably the gel composition comprises from about 18 percent by weight to about 22 percent by weight water. Preferably the gel composition comprises about 20 percent by weight water.

Preferably, the aerosol-forming substrate comprises between about 150 mg and about 350 mg of the gel composition.

As defined above, the aerosol generating articles of the present invention further comprise an upstream element located upstream of the aerosol-forming substrate.

The upstream element may be adjacent to the aerosol-forming substrate. The downstream end of the upstream element may abut the upstream end of the aerosol-forming substrate.

As used herein with reference to the invention, the terms “abutting” and “abut” are used to describe a component, or a portion of a component, being in direct contact with another component, or portion of a component.

Due to the provision of the recess extending from the upstream end of the aerosol generating article, through the upstream element, the upstream element will include a longitudinal opening to accommodate the recess. For example, the upstream element may have an annular shape.

The upstream element may be a porous plug element. Preferably, the upstream element has a porosity of at least about 50 percent in the longitudinal direction of the aerosol generating article. More preferably, the upstream element has a porosity of between about 50 percent and about 90 percent in the longitudinal direction. The porosity of the upstream element in the longitudinal direction is defined by the ratio of the cross-sectional area of material forming the upstream element and the internal cross-sectional area of the aerosol generating article at the position of the upstream element, excluding the longitudinal opening in the upstream element which is provided to accommodate the recess.

The upstream element may be made of a porous material or may comprise a plurality of openings. This may, for example, be achieved through laser perforation. Preferably, the plurality of openings is distributed homogeneously over the cross-section of the upstream element.

The porosity or permeability of the upstream element may advantageously be varied in order to provide a desirable overall resistance to draw of the aerosol generating article.

When the RTD of the upstream element are discussed herein, or when values for the RTD of the upstream element are given, it is assumed that air is unable to pass through the longitudinal opening of the upstream element. In practice, this may be true since the longitudinal opening may be occupied by a heater when the aerosol generating article is in use. As set out in more detail below, in the aerosol generating article according to the invention, it may not be intended that air should be able to enter the aerosol generating article through the recess and pass through the aerosol generating article to a user. Accordingly, when considering the RTD of the upstream element, it should be assumed that the longitudinal opening is blocked and that any air passing through the upstream element passes only through the material surrounding the longitudinal opening.

Preferably, the RTD of the upstream element is at least about 5 millimetres H2O. More preferably, the RTD of the upstream element is at least about 10 millimetres H2O. Even more preferably, the RTD of the upstream element is at least about 15 millimetres H2O. In particularly preferred embodiments, the RTD of the upstream element is at least about 20 millimetres H2O.

The provision of the upstream element having an RTD of at least about 20 millimetres H2

O advantageously substantially limits air entering the aerosol generating article through the upstream end. As a result, air flow through the aerosol generating article may be controlled only by configuring ventilation means, described in more detail below. This may advantageously simplify manufacture.

Furthermore, as set out above, the provision of an upstream element having a relatively high RTD may prevent or reduce air entering the aerosol generating article through the upstream end of the aerosol generating article. This may help prevent air passing through the aerosol-forming substrate which may advantageously prevent variations in RTD over the use of the aerosol generating article. In this way, the upstream element may also act as an RTD buffer to control the RTD of the article irrespective of the RTD of the other individual components of the article. In particular, the upstream element can advantageously be used to compensate for potential reductions in RTD due to evaporation of the gel composition during use, or due to the inclusion of other elements in the aerosol generating article having a relatively low resistance to draw.

The RTD of the upstream element is preferably less than or equal to about 80 millimetres H2O. More preferably, the RTD of the upstream element is less than or equal to about 60 millimetres H2O. Even more preferably, the RTD of the upstream element is less than or equal to about 40 millimetres H2O.

In some embodiments, the RTD of the upstream element is from about 5 millimetres H2O to about 80 millimetres H2O, preferably from about 10 millimetres H2O to about 80 millimetres H2O, more preferably from about 15 millimetres H2O to about 80 millimetres H2O, even more preferably from about 20 millimetres H2O to about 80 millimetres H2O. In other embodiments, the RTD of the upstream element is from about 5 millimetres H2O to about 60 millimetres H2O, preferably from about 10 millimetres H2O to about 60 millimetres H2O, more preferably from about 15 millimetres H2O to about 60 millimetres H2O, even more preferably from about 20 millimetres H2O to about 60 millimetres H2O. In further embodiments, the RTD of the upstream element is from about 5 millimetres H2O to about 40 millimetres H2O, preferably from about 10 millimetres H2O to about 40 millimetres H2O, more preferably from about 15 millimetres H2O to about 40 millimetres H2O, even more preferably from about 20 millimetres H2O to about 40 millimetres H2O.

Preferably, the RTD of the upstream element is greater than the RTD of the mouthpiece element, where present. Preferably, the RTD of the upstream element is at least 1.5 times the RTD of the mouthpiece element, more preferably at least 2 times the RTD of the mouthpiece element and more preferably at least 2.5 times the RTD of the mouthpiece element. This advantageously provides a greater proportion of the overall RTD of the aerosol generating article upstream of the rod of aerosol-forming substrate. This enables the RTD of the mouthpiece element to be minimized so that the filtration effect on the aerosol can also be minimized if desired.

The upstream element may be formed from a material that is impermeable to air. In such embodiments, the aerosol generating article may be configured such that air flows into the aerosol-forming substrate through suitable ventilation means provided in a wrapper.

The upstream element may be made of any material suitable for use in an aerosol generating article. The upstream element may, for example, be made of a same material as used for one of the other components of the aerosol generating article, such as a mouthpiece, or a cooling element. Suitable materials for forming the upstream element include filter materials, ceramic, polymer material, cellulose acetate, cardboard, high density crimped cotton, viscose, zeolite or aerosol-forming substrate.

The upstream element may comprise an annular plug comprising fibrous filtration material. Suitable fibrous filtration materials would be known to the skilled person. Particularly preferably, the upstream element comprises a cellulose acetate filter segment formed of cellulose acetate tow.

Preferably, the upstream element is formed of a heat resistant material. For example, preferably the upstream element is formed of a material that resists temperatures of up to 350 degrees Celsius. This ensures that the upstream element is not adversely affected by the heating means for heating the aerosol-forming substrate.

Preferably, the upstream element has a diameter that is approximately equal to the diameter of the aerosol generating article.

For example, the upstream element may have a diameter of between about 5 millimetres and about 15 millimetres, or between about 6 millimetres and about 9 millimetres.

Preferably, the upstream element has a length of between about 1 millimetre and about 10 millimetres, more preferably between about 3 millimetres and about 8 millimetres, more preferably between about 4 millimetres and about 6 millimetres. In a particularly preferred embodiment, the upstream element has a length of about 5 millimetres. The length of the upstream element can advantageously be varied in order to provide the desired total length of the aerosol generating article, or to ensure the aerosol-forming substrate is located at the optimum position for heating when the aerosol generating article is inserted into an aerosol generating device. For example, where it is desired to reduce the length of one of the other components of the aerosol generating article, the length of the upstream element may be increased in order to maintain the same overall length of the article.

The upstream element preferably has a substantially homogeneous structure. For example, the upstream element may be substantially homogeneous in texture and appearance. The upstream element may, for example, have a continuous, regular surface over its entire cross section. The upstream element may, for example, have no recognizable symmetries.

The upstream element is preferably circumscribed by a wrapper. The wrapper circumscribing the upstream element is preferably a stiff plug wrap, for example, a plug wrap having a basis weight of at least about 80 grams per square metre (gsm), or at least about 100 gsm, or at least about 110 gsm. This provides structural rigidity to the upstream element.

As defined above, the aerosol generating articles of the present invention further comprise a recess extending from the upstream end of the aerosol generating article, through the upstream element and through at least a portion of the aerosol-forming substrate.

The recess may be defined by a longitudinal opening extending though the upstream element and a longitudinal opening extending though at least a portion of the aerosol-forming substrate. The longitudinal opening extending though the upstream element and a longitudinal opening extending though at least a portion of the aerosol-forming substrate may have substantially the same diameter and be substantially aligned.

The recess may have any cross sectional shape. The recess may have a constant cross sectional shape. The shape of the recess may be configured to correspond to the shape of a heater of an aerosol generating device to be used with the aerosol generating article. The recess may have a circular cross sectional shape. A recess having a circular cross sectional shape may be appropriate where the heater is a pin heater. The recess may have an oblong or rectangular shape. A recess having an oblong or rectangular cross sectional shape may be appropriate where the heater is a blade heater. Preferably, the recess has a circular cross sectional shape.

The recess may be arranged centrally along the longitudinal axis of the aerosol generating article. This may advantageously simplify inserting the aerosol generating article into an aerosol generating device since the orientation of the aerosol generating device may not matter. Additionally, locating the recess centrally may advantageously ensure even heating of the aerosol-forming substrate.

The recess may have any diameter. Preferably, the recess has a diameter the same as, or slightly larger than, the diameter of a heater of an aerosol generating device to be used with the aerosol generating article.

The diameter of the recess may be between about 0.5 millimetres and about 10 millimetres. For example, the diameter of the recess may be between about 1 millimetre and about 8 millimetres, or between about 2 millimetres and about 6 millimetres. The recess may have any length. Preferably, the recess has a length the same as, or slightly larger than, the length of a heater of an aerosol generating device to be used with the aerosol generating article.

The length of the recess may be between about 5 millimetres and about 30 millimetres. For example, the length of the recess may be between about 10 millimetre and about 25 millimetres, or between about 15 millimetres and about 20 millimetres.

The recess may extend through the full length of the aerosol-forming substrate. Where this is the case, the recess may extend further downstream of the downstream end of the aerosol-forming substrate. Alternatively, where this is the case, the recess may extend to the downstream end of the aerosol-forming substrate but not extend any further downstream.

The inner surface of the recess may be provided with a wrapper. For example, the longitudinal inner surface of the recess may be provided with a wrapper. Where the recess has a circular cross-sectional shape, the wrapper may be provided on the curved longitudinal inner surface of the recess. The wrapper may therefore be between the upstream element and the recess, and between the aerosol-forming substrate and the recess.

The provision of a wrapper on the longitudinal inner surface of the recess may advantageously help to hold the components of the aerosol generating article in place. For example, the wrapper may advantageously prevent portions of the upstream element and the aerosol-forming substrate from entering the recess, which could otherwise prevent a heating element of an aerosol generating device from being inserted into the recess. Furthermore, the wrapper may act to provide a barrier between the aerosol-forming substrate and the recess. This may prevent direct contact between the aerosol-forming substrate and a heater of an aerosol generating article which may advantageously help to keep the heater clean.

The inventors have identified that where the aerosol-forming substrate is a gel, as is the case in the present invention, wrapper may readily stick to the aerosol-forming substrate on the inner surface of the recess thereby advantageously retaining the wrapper in the recess. This may be due to the relatively high moisture content of the gel aerosol-forming substrate. This synergistic effect may not be observed where the aerosol-forming substrate comprises, for example, tobacco.

The provision of the wrapper may reduce or prevent air passing from the recess into the aerosol generating article. This may advantageously improve the control of the airflow through the aerosol generating article. As set out in more detail below, in the aerosol generating article according to some aspects of the invention, it is not intended that air should be able to enter the aerosol generating article through the recess and pass through the aerosol generating article to a user.

The wrapper may extend along the full length of the longitudinal inner surface of the recess. In other words, the wrapper may extend from the upstream end of the recess to the downstream end of the recess.

The wrapper may be provided on the entire longitudinal inner surface of the recess. In other words, all of the longitudinal inner surface of the recess may be covered by the wrapper. This may advantageously help to fully separate the aerosol-forming substrate and the recess.

The wrapper may be formed from any suitable material. For example, the wrapper may comprise paper, preferably cellulose-based paper.

The wrapper may be a hydrophobic wrapper. The term “hydrophobic” refers to a surface exhibiting water repelling properties. One useful way to determine this is to measure the water contact angle. The “water contact angle” is the angle, conventionally measured through the liquid, where a liquid/vapour interface meets a solid surface. It quantifies the wettability of a solid surface by a liquid via the Young equation. Hydrophobicity or water contact angle may be determined by utilizing TAPPI T558 test method and the result is presented as an interfacial contact angle and reported in “degrees” and can range from near zero to near 180 degrees.

In preferred embodiments, the hydrophobic wrapper is one including a paper layer having a water contact angle of about 30 degrees or greater, and preferably about 35 degrees or greater, or about 40 degrees or greater, or about 45 degrees or greater.

By way of example, the paper layer may comprise PVOH (polyvinyl alcohol) or silicon. The PVOH may be applied to the paper layer as a surface coating, or the paper layer may comprise a surface treatment comprising PVOH or silicon.

The provision of a hydrophobic wrapper may be particularly advantageous where the gel aerosol-forming substrate has a high moisture content as it may help to maintain the structural integrity of the aerosol generating article.

The wrapper may comprise a metallic layer. The metallic layer may be in combination with another layer. For example, the metallic layer may be used in combination with a paper layer. Where this is the case, the metallic layer may be disposed between the aerosol-forming substrate or the upstream element, and the paper layer. This may separate the paper from the aerosol-forming substrate which may advantageously prevent the gel aerosol-forming substrate from coming into direct contact with the paper. Alternatively, the paper layer may be disposed between the aerosol-forming substrate or the upstream element, and the metallic layer. This may prevent the paper layer from being in direct contact, or close to, the heater of an aerosol generating device which may advantageously prevent the paper from burning.

The wrapper may comprise a plurality of metallic layers. The wrapper may comprise a plurality of paper layers.

The metallic layer of the wrapper may have any thickness. For example, the metallic layer may have a thickness of between about 2 micrometres and about 40 micrometres, or between about 5 micrometres and about 30 micrometres. The metallic layer may comprise aluminium foil. The metallic layer may be co-laminated with a paper layer.

The wrapper may have any overall thickness. For example, the wrapper may have a thickness of between about 30 micrometres and about 200 micrometres, between about 50 micrometres and about 180 micrometres, or between about 60 and about 150 micrometres.

The downstream end of the recess may be defined by a wrapper. The downstream end of the recess refers to the end face at the furthest downstream end of the recess as opposed to the longitudinal inner surface of the recess. The wrapper may be formed from any of the materials set out above in relation to the wrapper provided on the longitudinal inner surface of the recess. The provision of a wrapper defining the downstream end of the recess may advantageously reduce or prevent air entering the aerosol generating article through the recess.

The wrapper defining the downstream end of the recess may be formed from the same piece of material as the wrapper provided on the longitudinal inner surface of the recess.

Where this is the case, the wrapper which is provided on the longitudinal inner surface of the recess also extends over the downstream end of the recess. The wrapper may be mechanically closed at the downstream end of the recess. This may be achieved by folding or twisting the wrapper. An adhesive may be used to close the downstream end of the recess.

This provision may advantageously simplify manufacture of the aerosol generating article since only one piece of wrapper material may be needed. In addition, the use of a single piece of wrapper material may remove the need for a seam to connect two pieces of wrapper material. This may advantageously simplify manufacture. The lack of a seam may also advantageously prevent or reduce any of the aerosol-forming substrate from leaking out of the aerosol generating article.

At least one of the aerosol-forming substrate and the upstream element may be circumscribed by a wrapper.

As used herein with reference to the invention, the terms “circumscribe” and “circumscribing” refer to a first feature extending around the entire circumference of a second feature. For example, in the present invention a wrapper may circumscribe at least one of the aerosol-forming substrate and the upstream element. This means that at one or more points along the longitudinal length of at least one of the aerosol-forming substrate and the upstream element, the wrapper extends around the entire circumference of the at least one of the aerosol-forming substrate and the upstream element.

The wrapper may be formed from any of the materials set out above in relation to the wrapper provided on the longitudinal inner surface of the recess.

The wrapper may advantageously act to secure the aerosol-forming substrate to the upstream element. Where the wrapper circumscribes the aerosol-forming substrate, the wrapper may advantageously prevent a user from coming into contact with the aerosol-forming substrate. In addition, the wrapper may circumscribe other components of the aerosol generating article such as a mouthpiece assembly.

The wrapper may extend over the full length of the aerosol generating article. In other words, the wrapper may extend from the upstream end of the aerosol generating article to the downstream end of the aerosol generating article.

The wrapper circumscribing least one of the aerosol-forming substrate and the upstream element may formed from the same piece of material as the wrapper provided on the longitudinal inner surface of the recess. Where this is the case, a wrapper is provided on the longitudinal inner surface of the recess, and the same wrapper extends out of the upstream end of the recess, across the upstream end surface of the aerosol generating article and about at least a portion of at least one of the aerosol-forming substrate and the upstream element such that at least one of the aerosol-forming substrate and the upstream element is circumscribed by the wrapper.

This provision may advantageously simplify manufacture of the aerosol generating article since only one piece of wrapper material may be needed. In addition, the use of a single piece of wrapper material may remove the need for a seam to connect two pieces of wrapper material. This may advantageously simplify manufacture. The lack of a seam may also advantageously prevent or reduce any of the aerosol-forming substrate from leaking out of the aerosol generating article.

The wrapper may be provided on at least a portion of the upstream end of the aerosol generating article. Where the upstream element is the most upstream component of the aerosol generating article, the wrapper may be provided on the upstream end of the upstream element. The wrapper may be provided on only a portion of the upstream end surface of the aerosol generating article. Preferably, the wrapper may be provided on the entire upstream end surface of the aerosol generating article. Where this is the case, it is understood that the upstream end of the recess remains open and uncovered.

The downstream end of the recess may be defined by a downstream element. The downstream element may comprise a plug of material. The plug of material may have a resistance to draw of at least 20 millimetres H₂O.

The provision of a downstream element at the downstream end of the recess may advantageously reduce or prevent air entering the aerosol generating article through the recess. Furthermore, the downstream element may advantageously strengthen the downstream end of the recess. This may be particularly apparent when compared to examples of the present invention in which the downstream end of the recess is defined by a wrapper.

The wrapper provided on longitudinal inner surface of the recess may circumscribe at least a portion of the downstream element. Thus may advantageously help to maintain the structure of the recess.

The downstream element may have any of the materials properties described above in relation to the upstream element.

In particular, the downstream element may be a porous plug element. Preferably, a porous plug element does not alter the resistance to draw of the aerosol generating article. Preferably, the downstream element has a porosity of at least about 50 percent in the longitudinal direction of the aerosol generating article. More preferably, the downstream element has a porosity of between about 50 percent and about 90 percent in the longitudinal direction. The porosity of the downstream element in the longitudinal direction is defined by the ratio of the cross-sectional area of material forming the downstream element and the internal cross-sectional area of the aerosol generating article at the position of the downstream element.

The downstream element may be made of a porous material or may comprise a plurality of openings. This may, for example, be achieved through laser perforation. Preferably, the plurality of openings is distributed homogeneously over the cross-section of the downstream element.

The porosity or permeability of the downstream element may advantageously be varied in order to provide a desirable overall resistance to draw of the aerosol generating article.

The provision of the downstream element having an RTD of at least about 20 millimetres H2O advantageously substantially limits air entering the aerosol generating article through the downstream end. As a result, air flow through the aerosol generating article may be controlled only by configuring ventilation means, described in more detail below. This may advantageously simplify manufacture.

The RTD of the downstream element is preferably less than or equal to about 80 millimetres H2O. More preferably, the RTD of the downstream element is less than or equal to about 60 millimetres H2O. Even more preferably, the RTD of the downstream element is less than or equal to about 40 millimetres H2O.

The downstream element may be formed from a material that is impermeable to air. In such embodiments, the aerosol generating article may be configured such that air flows into the aerosol-forming substrate through suitable ventilation means provided in a wrapper.

The downstream element may be made of any material suitable for use in an aerosol generating article. The downstream element may, for example, be made of a same material as used for one of the other components of the aerosol generating article, such as a mouthpiece, or a cooling element. Suitable materials for forming the downstream element include filter materials, ceramic, polymer material, cellulose acetate, cardboard, high density crimped cotton, viscose, zeolite or aerosol-forming substrate.

In some embodiments, the downstream element is formed from the same material as the upstream element. This may advantageously simplify manufacture of the aerosol generating article.

Preferably, the downstream element has a diameter that is approximately equal to the diameter of the recess. For example, the downstream of the downstream element may be between about 0.5 millimetres and about 10 millimetres. For example, the diameter of the downstream element may be between about 1 millimetre and about 8 millimetres, or between about 2 millimetres and about 6 millimetres.

Preferably, the downstream element has a length of between about 1 millimetre and about 10 millimetres, more preferably between about 3 millimetres and about 8 millimetres, more preferably between about 4 millimetres and about 6 millimetres. In a particularly preferred embodiment, the downstream element has a length of about 5 millimetres.

The aerosol generating article may further comprise a mouthpiece assembly. The mouthpiece assembly is provided downstream of the aerosol-forming substrate. The mouthpiece assembly may comprise a single component. The mouthpiece assembly may comprise a plurality of components. The mouthpiece assembly may include one or more of a cooling element, a filter element, or a spacer element.

The mouthpiece assembly may comprise a first tube. The mouthpiece assembly may comprise a second tube. The mouthpiece assembly may comprise a third tube. The first tube may abut a downstream end face of the second tube. The third tube may abut an upstream end face of the second tube. An internal diameter of the second tube may be smaller than an internal diameter of the first tube. The internal diameter of the second tube may be smaller than an internal diameter of the third tube. The internal diameter of the first tube may be at least about 3 millimetres.

The aerosol generating article comprising a mouthpiece assembly being formed from a plurality of tubes, with the second tube a narrower diameter than the first and third tubes, may result in an increased amount of aerosol that can be drawn out of the aerosol generating article. This increased amount of aerosol can improve the user's experience.

The first tube may have an internal diameter of between about 3 millimetres and about 8 millimetres. For example, the first tube may have an internal diameter of between about 3.3 millimetres and about 6 millimetres, or between about 3.5 millimetres and about 5 millimetres, or between about 3.7 millimetres and about 4.5 millimetres. For example, the first tube may have an internal diameter of about 4 millimetres.

The first tube may have a length of between about 4 millimetres and about 6 millimetres. For example, the first tube may have a length of between about 4.5 millimetres and about 5.5 millimetres. The first tube may have a length of about 5 millimetres.

The second tube may have an internal diameter of between about 1 millimetre and about 3 millimetres. For example, the second tube may have an internal diameter of between about 1.3 millimetres and about 2.7 millimetres, or between about 1.5 millimetres and about 2.5 millimetres, or between about 1.8 millimetres and about 2.2 millimetres. For example, the second tube may have an internal diameter of about 2 millimetres.

The second tube may have a length of between about 4 millimetres and about 6 millimetres. For example, the second tube may have a length of between about 4.5 millimetres and about 5.5 millimetres. The second tube may have a length of about 5 millimetres.

The third tube may have an internal diameter of between about 3 millimetres and about 8 millimetres. For example, the third tube may have an internal diameter of between about 3.3 millimetres and about 6 millimetres, or between about 3.5 millimetres and about 5 millimetres, or between about 3.7 millimetres and about 4.5 millimetres. For example, the third tube may have an internal diameter of about 4millimetres.

The third tube may have a length of between about 4 millimetres and about 8 millimetres. For example, the third tube may have a length of between about 4.5 millimetres and about 7.5 millimetres, or between about 5 millimetres and about 7 millimetres. The third tube may have a length of about 5 millimetres. The third tube may have a length of about 6 millimetres.

The ratio of the internal diameter of the first tube to the internal diameter of the second tube may be between about 1.2 and about 5. For example, the ratio of the internal diameter of the first tube to the internal diameter of the second tube may be between about 1.4 and about 4, or between about 1.6 and about 3, or between about 1.8 and about 2.5. The ratio of the internal diameter of the first tube to the internal diameter of the second tube may be about 2.

The ratio of the internal diameter of the first tube to the internal diameter of the third tube may be between about 0.5 and about 2. For example, the ratio of the internal diameter of the first tube to the internal diameter of the third tube may be between about 0.7 and about 1.3, or between about 0.8 and about 1.2, or between about 0.9 and about 1.1, or between about 0.95 and about 1.05. The ratio of the internal diameter of the first tube to the internal diameter of the third tube may be about 1.

The ratio of the internal diameter of the third tube to the internal diameter of the second tube may be between about 1.2 and about 5. For example, the ratio of the internal diameter of the third tube to the internal diameter of the second tube may be between about 1.4 and about 4, or between about 1.6 and about 3, or between about 1.8 and about 2.5. The ratio of the internal diameter of the third tube to the internal diameter of the second tube may be about 2.

The first tube may be located at the downstream end of the mouthpiece assembly. The first tube may have a uniform internal diameter. In other words, the internal diameter of the first tube may be the same along its whole length.

Alternatively, the first tube may have a changing internal diameter. In other words, the internal diameter of the first tube may vary along its length. For example, the internal diameter of the first tube may increase from one end to another. The internal diameter of the first tube may decrease from one end to another.

In a particular example, the internal diameter of the first tube may increase from the upstream end of the first tube to the downstream end of the first tube. In other words, the internal diameter of the first tube at its downstream end is larger than the internal diameter of the first tube at its upstream end. Advantageously, this “funneling out” of the internal diameter of the first tube improves the taste of the aerosol.

In an example of a first tube having a changing internal diameter, the internal diameter of the first tube is considered to be the mean diameter of the first tube.

The internal diameter of the first tube may be larger than the internal diameter of the third tube.

Advantageously, the internal diameter of the first tube being larger than the internal diameter of the third tube may further improve the user's filling perception.

The second tube may have a uniform internal diameter. In other words, the internal diameter of the second tube may be the same along its whole length.

In an example of a second tube having a uniform internal diameter, the internal diameter of the second tube is considered to be the fixed diameter of the second tube.

Alternatively, the second tube may have a changing internal diameter. In other words, the internal diameter of the second tube may vary along its length. For example, the internal diameter of the second tube may increase from one end to another. The internal diameter of the second tube may decrease from one end to another.

The third tube may have a uniform internal diameter. In other words, the internal diameter of the third tube may be the same along its whole length.

In an example of a third tube having a uniform internal diameter, the internal diameter of the third tube is considered to be the fixed diameter of the third tube.

Alternatively, the third tube may have a changing internal diameter. In other words, the internal diameter of the third tube may vary along its length. For example, the internal diameter of the third tube may decrease from one end to another. The internal diameter of the third tube may increase from one end to another.

One or more of the first tube, the second tube and the third tube may be a cellulose acetate tube. In other words, one or more of the first tube, the second tube and the third tube may be formed from cellulose acetate. For example, the first tube may be a cellulose acetate tube. The second tube may be a cellulose acetate tube. The third tube may be a cellulose acetate tube.

A cellulose acetate tube may alternatively be referred to as a “hollow acetate tube” or a HAT.

Advantageously, forming the first tube from cellulose acetate can further improve the rigidity and resilience of the mouthpiece assembly, which improves the user experience. In addition, since cellulose acetate is substantially impermeable to water, forming the first tube from cellulose acetate may result in a mouthpiece assembly that is less sensitive to the humidity of a user's mouth.

The mouthpiece assembly may abut the downstream end of the aerosol-forming substrate. Alternatively, the mouthpiece assembly may be spaced apart from the aerosol-forming substrate.

The provision of the mouthpiece assembly being spaced apart from the aerosol-forming substrate may advantageously provide a space downstream of the aerosol-forming substrate where the aerosol may cool, condense and nucleate.

The portion between the aerosol-forming substrate and the mouthpiece may include a tube. The tube may advantageously strengthen the aerosol generating article while still providing a space for the aerosol to cool.

The upstream end of the mouthpiece assembly may be between 1 millimetre and 20 millimetres from the downstream end of the aerosol-forming substrate. For example, the upstream end of the mouthpiece assembly may be between 2 millimetres and 10 millimetres from the downstream end of the aerosol-forming substrate.

The aerosol generating article may comprise at least one ventilation zone to allow air to enter the aerosol generating article.

The provision of at least one ventilation zone may advantageously allow air to enter the aerosol generating article and entrain an aerosol from the aerosol-forming substrate.

The at least one ventilation zone may comprise a plurality of perforations. Preferably, the at least one ventilation zone comprises at least one circumferential row of perforations about the longitudinal surface of the aerosol generating article. In some embodiments, the ventilation zone may comprise two circumferential rows of perforations. For example, the perforations may be formed online during manufacturing of the aerosol generating article. Preferably, each circumferential row of perforations comprises from 8 to 30 perforations. The perforations may be provided by any means. For example, the perforations may be provided by laser perforating techniques.

The at least one ventilation zone may be provided downstream of the aerosol-forming substrate. For example, the at least one ventilation zone may be provided about the mouthpiece assembly. Where the at least one ventilation zone is provided about the mouthpiece assembly, it is preferable that the at least one ventilation zone is provided about the upstream end of the mouthpiece assembly. It will be understood that the “upstream end” of the mouthpiece assembly refers to anywhere in the upstream half of the mouthpiece assembly. This may advantageously help to maximize the aerosol entrained in the airflow through the article since the air will enter the aerosol generating article close to the aerosol-forming substrate. For example, the at least one ventilation zone may be provided about the third tube of the mouthpiece assembly.

Alternatively, or in addition, the at least one ventilation zone may be provided about the space between the mouthpiece assembly and the aerosol-forming substrate.

The at least one ventilation zone may be provided about the aerosol-forming substrate.

The at least one ventilation zone may be provided at the downstream end of the recess. In this case, the perforations may be provided through the wrapper which defines the downstream end of the recess, or, where present, through the downstream element defining the downstream end of the recess. This may allow air to pass from the recess into the aerosol generating article.

The aerosol generating article may have any dimensions. The aerosol generating article may have a diameter of between about 5 millimetres and about 15 millimetres, or between about 6 millimetres and about 9 millimetres. The aerosol generating article may have a length of between about 20 millimetres and about 80 millimetres, or between about 30 millimetres and about 60 millimetres, or between about 40 millimetres and about 50 millimetres.

The aerosol generating article according to the present invention is intended to be used in combination with an aerosol generating device. The aerosol generating device may be an electrically heated aerosol generating device. Where this is the case, the aerosol generating device may comprise an electrical power source, such as a battery, control electronics, and an electrical heater. The electrical heater may be a resistance heater and may take the form of a blade or a pin. Alternatively, the electrical heater may be an induction heater comprising an elongate susceptor configured to be received by the recess of the aerosol generating article of the present invention, and at least one induction coil configured to inductively heat the susceptor.

According to the present disclosure, there is also provided an aerosol generating system comprising an aerosol generating article according to the present invention, and an aerosol generating device as described above.

The invention is defined in the claims. However, below there is provided a non-exhaustive list of non-limiting examples. Any one or more of the features of these examples may be combined with any one or more features of another example, embodiment, or aspect described herein.

Example Ex1. An aerosol generating article for producing an inhalable aerosol upon heating, the aerosol generating article comprising:

an aerosol-forming substrate comprising a gel composition, the gel composition comprising at least one gelling agent, at least one of an alkaloid compound and a cannabinoid compound, and an aerosol former ;

an upstream element upstream of the aerosol-forming substrate; and

a recess extending from the upstream end of the aerosol generating article, through the upstream element and through at least a portion of the aerosol-forming substrate.

Example Ex2. An aerosol generating article according to example 1, wherein the upstream element comprises an annular plug comprising fibrous filtration material.

Example Ex 3. An aerosol generating article according to example 2, wherein the resistance to draw of the upstream element is at least 20 millimetres H2O.

Example Ex 4. An aerosol generating article according to any preceding example, wherein the longitudinal inner surface of the recess is provided with a wrapper.

Example Ex 5. An aerosol generating article according to example 4, wherein at least one of the aerosol-forming substrate and the upstream element is circumscribed by a wrapper.

Example Ex 6. An aerosol generating article according to example 5, wherein the wrapper circumscribing least one of the aerosol-forming substrate and the upstream element is formed from the same piece of material as the wrapper provided on the longitudinal inner surface of the recess.

Example Ex 7. An aerosol generating article according to any one of example 4 to 6, wherein the downstream end of the recess is defined by a wrapper.

Example Ex 8. An aerosol generating article according to example 7, wherein the wrapper defining the downstream end of the recess is formed from the same piece of material as the wrapper provided on the longitudinal inner surface of the recess.

Example Ex 9. An aerosol generating article according to any preceding example, wherein the downstream end of the recess is defined by a downstream element, the downstream element comprising a plug of material.

Example Ex 10. An aerosol generating article according to any preceding example, further comprising a mouthpiece assembly downstream of the aerosol-forming substrate.

Example Ex 11. An aerosol generating article according to example 10, wherein the mouthpiece assembly is spaced apart from the aerosol-forming substrate.

Example Ex 12. An aerosol generating article according to example 11, wherein the upstream end of the mouthpiece assembly is between 1 millimetres and 20 millimetres from the downstream end of the aerosol-forming substrate.

Example Ex 13. An aerosol generating article according to any preceding example, further comprising at least one ventilation zone to allow air to enter the aerosol generating article.

Example Ex 14. An aerosol generating article according to example 13, wherein the at least one ventilation zone is disposed about at least one of the aerosol-forming substrate and the mouthpiece assembly.

Example Ex 15. An aerosol generating article according to example 14, wherein the at least one ventilation zone is disposed about the upstream end of the mouthpiece assembly.

Example Ex 16. An aerosol generating article according to any preceding example, wherein the aerosol-forming substrate comprises an annular plug of a porous medium loaded with the gel composition.

Example Ex 17. An aerosol generating article according to example 16, wherein the porous medium is in the form of a crimped sheet.

Example Ex 18. An aerosol generating article according to example 16 or 17, wherein the porous medium comprises cotton fibres.

Example Ex 19. An aerosol generating article according to any of example 16 to 18, wherein the plug of the porous medium loaded with the gel composition is circumscribed by a water repellent wrapper.

Example Ex 20. An aerosol generating article according to any preceding example, wherein the gel composition comprises at least 0.5 percent by weight of nicotine.

Example Ex 21. An aerosol generating system comprising an aerosol generating article according to any preceding example, and an aerosol generating device.

Examples will now be further described with reference to the figures in which:

FIG. 1 shows a schematic side sectional view of an aerosol generating article in accordance with the invention; and

FIG. 2 shows a schematic side sectional view of another aerosol generating article in accordance with the invention.

As shown in FIG. 1 , the aerosol generating article 100 comprises an aerosol-forming substrate 101 downstream of an upstream element 102.

The aerosol-forming substrate 101 comprises an annular plug of porous medium loaded with a gel composition as defined above. Examples of suitable gel compositions are shown below in Table 1. Proportions of each component of each example gel composition are given in weight percentages:

TABLE 1 Exam- Exam- Exam- Exam- Exam- ple 1 ple 2 ple 3 ple 4 ple 5 Component (wt %) (wt %) (wt %) (wt %) (wt %) Water 20 — 20 20 24.42 Glycerol 73.5 95.2 72.7 72.7 48 Nicotine 1.5 2 2 2 1.44 Gelling agent 3 — — 19.27 Lactic acid 1 — — 1.3 Divalent cations 1 — — Low Acyl Gellan — 0.5 1 1 Guar — 0.5 — Calicum — 0.5 0.5 0.3 Levulinic acid — 1.3 1.3 2.07 Xanthan 1 1 Agar 1 1 4.8

The aerosol-forming substrate 101 has a length of about 10 millimetres.

The upstream element 102 is disposed immediately upstream of the aerosol-forming substrate 101 and abuts the aerosol-forming substrate 101. The upstream element 102 comprises an annular plug comprising fibrous filtration material. In this example embodiment, the upstream element 102 comprises an annular plug of cellulose acetate circumscribed by a stiff wrapper. The upstream element 102 has a length of about 5 millimetres. The RTD of the upstream element 102 is about 30 millimetres H2O.

The aerosol generating article 100 further comprises a recess 103 extending from the upstream end of the aerosol generating article 100, through the upstream element 102 and through at least a portion of the aerosol-forming substrate 101.

The recess 103 is located along the central axis of the aerosol generating article 100. The recess 103 has a circular cross sectional shape. In the example shown, the recess 103 extends the full length of both the upstream element 102 and the aerosol-forming substrate 101 by passing through both the annular plug comprising fibrous filtration material of the upstream element 102, and the annular plug of porous medium of the aerosol-forming substrate 101. The recess 103 has a length of about 15 millimetres, corresponding to the combined length of the upstream element 102 and the aerosol-forming substrate 101. The recess has a diameter of about 4 millimetres.

The aerosol generating article 100 of the present invention further comprises a wrapper 104. The wrapper 104 is provided on the longitudinal inner surface of the recess. The wrapper 104 extends the full length of the recess 103 and is provided on the entire longitudinal inner surface of the recess 103.

In the embodiment shown in FIG. 1 , the downstream end of the recess 103 is defined by the wrapper. This is achieved by mechanically folding the wrapper at the downstream end of the recess.

The wrapper 104 extends out of the upstream end of the recess 103 and over the upstream end of the aerosol generating article 100. The wrapper 104 also extends over the entire outer surface of the aerosol generating article 100. In this way, the wrapper 104 acts to connect the various components of the aerosol generating article 104.

The wrapper 104 comprises a cellulose based paper layer co-laminated with a layer of aluminium foil. The wrapper 104 is arranged so that the paper layer is on the outer surface of the aerosol generating article 100.

The aerosol generating article 100 further comprises a multi segment mouthpiece assembly 105.

The multi segment mouthpiece assembly 105 comprises a first tube 110, a second tube 109, and a third tube 108. The downstream end of the third tube 108 abuts the upstream end of the second tube 109, and the downstream end of the second tube 109 abuts the upstream end of the first tube 110.

The internal diameter of the first tube 110 is about 4 millimetres. The internal diameter of the second tube 109 is about 2 millimetres. The internal diameter of the third tube 108 is about 3.5 millimetres.

The first, second, and third tubes 110, 109, 108 are cellulose acetate tubes.

The first and second tubes 110, 109 each have length of about 5 millimetres. The third tube 108 has a length of about 6 millimetres.

Air inlets 107 are provided about the third tube 108. The air inlets 107 extend through the wrapper 104 to allow air to enter the aerosol generating article 100.

The mouthpiece assembly 105 is spaced apart from the aerosol-forming substrate 101 by about 5 millimetres.

In use, the aerosol generating article 100 is inserted into an aerosol generating device. A heating element from the aerosol generating device in turn, is inserted into the recess 103 of the aerosol generating article 100. The aerosol generating device is activated and the heating element heats up. The heating element heats the aerosol-forming substrate 101 of the aerosol generating article 100. The gel composition of the aerosol-forming substrate 101 generates a vapour which cools and nucleates into an aerosol in the space 106 between the mouthpiece assembly 105 and the aerosol-forming substrate 101.

A pressure drop at the downstream end of the aerosol generating article 100 draws air into the aerosol generating article 100 through the air inlets 107. The air drawn though the air inlets 107 entrains vapour from the aerosol-forming substrate 101. This air entrained with vapour then passes through the mouthpiece 105 and out of the downstream end of the aerosol generating article 100.

An alternative aerosol generating article 200 according to the invention is shown in FIG. 2 . The aerosol generating article 200 shown in FIG. 2 is similar to the aerosol generating article 100 shown in FIG. 1 and like reference numerals are used to refer to like features.

The aerosol generating article 200 of FIG. 2 differs from the aerosol generating article 100 of FIG. 1 in that the downstream end of the recess 103 is defined by a downstream element 111. The downstream element 111 comprises a plug comprising fibrous filtration material. In this example embodiment, the downstream element 111 comprises a plug of cellulose acetate. The downstream element 111 has a length of about 5 millimetres. The RTD of the downstream element 111 is about 30 millimetres H2O.

Rather than being mechanically folded at the downstream end of the recess 103 as it is in the aerosol generating article 100 of FIG. 1 , the wrapper 104 of the aerosol generating article 200 of FIG. 2 circumscribes the downstream element 111.

For the purpose of the present description and of the appended claims, except where otherwise indicated, all numbers expressing amounts, quantities, percentages, and so forth, are to be understood as being modified in all instances by the term “about”. Also, all ranges include the maximum and minimum points disclosed and include any intermediate ranges therein, which may or may not be specifically enumerated herein. In this context, therefore, a number A is understood as A±10% of A. Within this context, a number A may be considered to include numerical values that are within general standard error for the measurement of the property that the number A modifies. The number A, in some instances as used in the appended claims, may deviate by the percentages enumerated above provided that the amount by which A deviates does not materially affect the basic and novel characteristic(s) of the claimed invention. Also, all ranges include the maximum and minimum points disclosed and include any intermediate ranges therein, which may or may not be specifically enumerated herein. 

1.-14. (canceled)
 15. An aerosol-generating article for producing an inhalable aerosol upon heating, the aerosol-generating article comprising: an aerosol-forming substrate comprising a gel composition, the gel composition comprising at least one gelling agent, at least one of an alkaloid compound and a cannabinoid compound, and an aerosol former; an upstream element upstream of the aerosol-forming substrate; and a recess extending from an upstream end of the aerosol-generating article, through the upstream element, and through at least a portion of the aerosol-forming substrate, wherein a longitudinal inner surface of the recess is provided with a wrapper.
 16. The aerosol-generating article according to claim 15, wherein the upstream element comprises an annular plug comprising fibrous filtration material.
 17. The aerosol-generating article according to claim 16, wherein a resistance-to-draw of the upstream element is at least 20 millimetres H₂O.
 18. The aerosol-generating article according to claim 15, wherein at least one of the aerosol-forming substrate and the upstream element is circumscribed by another wrapper.
 19. The aerosol-generating article according to claim 18, wherein the another wrapper circumscribing the least one of the aerosol-forming substrate and the upstream element is formed from a same piece of material as the wrapper provided on the longitudinal inner surface of the recess.
 20. The aerosol-generating article according to claim 15, wherein a downstream end of the recess is defined by another wrapper.
 21. The aerosol-generating article according to claim 20, wherein the another wrapper defining the downstream end of the recess is formed from a same piece of material as the wrapper provided on the longitudinal inner surface of the recess.
 22. The aerosol-generating article according to claim 15, wherein a downstream end of the recess is defined by a downstream element, the downstream element comprising a plug of material.
 23. The aerosol-generating article according to claim 15, further comprising a mouthpiece assembly downstream of the aerosol-forming substrate.
 24. The aerosol-generating article according to claim 23, wherein the mouthpiece assembly is spaced apart from the aerosol-forming substrate.
 25. The aerosol-generating article according to claim 24, wherein an upstream end of the mouthpiece assembly is between 1 millimetre and 20 millimetres from a downstream end of the aerosol-forming substrate.
 26. The aerosol-generating article according to claim 23, further comprising at least one ventilation zone configured to allow air to enter the aerosol-generating article.
 27. The aerosol-generating article according to claim 26, wherein the at least one ventilation zone is disposed about at least one of the aerosol-forming substrate and the mouthpiece assembly.
 28. The aerosol-generating article according to claim 27, wherein the at least one ventilation zone is disposed about an upstream end of the mouthpiece assembly. 